The '''parallel axis theorem''', also known as '''Huygens–Steiner theorem''', or just as '''Steiner's theorem''',<ref>{{cite book | title=Introduction to theoretical physics | author=Arthur Erich Haas | year=1928}}</ref> named after [[Christiaan Huygens]] and [[Jakob Steiner]], can be used to determine the [[moment of inertia]] or the [[second moment of area]] of a [[rigid body]] about any axis, given the body's moment of inertia about a [[Parallel (geometry)|parallel]] axis through the object's [[center of gravity]] and the [[perpendicular]] [[distance]] between the axes.
